Blocks

Blocks

Almost any Ruby method call can accept an attached block, written with { ... } or do ... end, which the method can run zero or more times using yield. Blocks are how iteration methods like each and map receive the logic to run per element. Unlike a Proc or Lambda, a block is not itself an object -- it's syntax tied directly to a single method call.

Note: Use { } for short, single-line blocks and do...end for longer, multi-line blocks -- this is the community style convention.

Example: Blocks

[1, 2, 3].each { |n| puts "Value: #{n}" }

[1, 2, 3].each do |n|
  doubled = n * 2
  puts "Doubled: #{doubled}"
end